Ocean Wave Measurement Using GPS Buoys

Joodaki, Gholamreza; Nahavandchi, Hossein; Cheng, Kevin

doi:10.2478/jogs-2013-0023

Cited by 20 publications

(11 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This choice was based on our long experience that there is practically no physically meaningful wave data below that frequency in the Baltic Sea (e.g. Kahma, 1981;Kahma et al, 2003;Pettersson, 2004;Tuomi, 2008;Tuomi et al, 2011). For the purpose of our calculations we can therefore assume that frequencies below 0.07 Hz contain only pure erroneous trend.…”

Section: The Correction Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Removing low-frequency artefacts from Datawell DWR-G4 wave buoy measurements

Björkqvist¹,

Pettersson²,

Laakso³

et al. 2016

Geosci. Instrum. Method. Data Syst.

View full text Add to dashboard Cite

Abstract. In this study we describe a previously unreported error in the vertical-displacement time series made with GPS-based Datawell DWR-G4 wave buoys and introduce a simple method to correct the resulting wave spectra. The artefact in the time series is found to resemble a sawtooth wave, which produces an erroneous trend following an f−2 power law in frequency space. The correction method quantifies the amount of erroneous trend below a certain maximum frequency and removes the spurious energy from all frequencies assuming the above-mentioned f−2 power law. The presented correction method is validated against an experimental field test, and its impact on the measured significant wave height is quantified. The method's sensitivity to the choice of the maximum frequency is also briefly discussed.

show abstract

Section: The Correction Methodsmentioning

confidence: 99%

“…We at the Finnish Meteorological Institute 1 (FMI) have observed waves in the Baltic Sea since the 1970s both campaign-based (e.g. Kahma, 1981;Pettersson, 2004;Tuomi et al, 2014) and operationally (e.g. Pettersson and Jönsson, 2004;Tuomi, 2008).…”

Section: Methodsmentioning

confidence: 99%

Removing low-frequency artefacts from Datawell DWR-G4 wave buoy measurements

Björkqvist¹,

Pettersson²,

Laakso³

et al. 2016

Geosci. Instrum. Method. Data Syst.

View full text Add to dashboard Cite

show abstract

“…Differences in the low-frequency regime between the conventional sensors can be also due to errors associated with GPS positioning data. GPS measurements include a number of errors, including satellite-dependent errors, signal propagation errors, and receiver-dependent errors [25]. The majority of these positioning errors impact the power spectrum at low frequencies (< 0.01 Hz), but could have slight influences at frequencies between 0.01 and 0.05 Hz [25]; see [25] for further details.…”

Section: Comparison With Conventional Sensor Datamentioning

confidence: 99%

“…GPS measurements include a number of errors, including satellite-dependent errors, signal propagation errors, and receiver-dependent errors [25]. The majority of these positioning errors impact the power spectrum at low frequencies (< 0.01 Hz), but could have slight influences at frequencies between 0.01 and 0.05 Hz [25]; see [25] for further details. This effect is mitigated by high-pass filtering the data, which was performed for these data sets at a cutoff frequency of 0.04 Hz.…”

Section: Comparison With Conventional Sensor Datamentioning

confidence: 99%

Comparison of Incoherent and Coherent Wave Field Measurements Using Dual-Polarized Pulse-Doppler X-Band Radar

Hackett

Fullerton

Merrill

et al. 2015

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

Radar-based remote sensing for measurement of ocean surface waves presents advantages over conventional point sensors such as wave buoys. As its use becomes more widespread, it is important to understand the sensitivity of the extracted wave parameters to the characteristics of the radar and the scatterers. To examine such issues, experiments were performed offshore of the Scripps Institution of Oceanography pier in July 2010. Radar measurements in low wind speeds were performed with a dual-polarized high-resolution X-band pulse-Doppler radar at low grazing angles along with two independent measurements of the surface waves using conventional sensors, a GPS-based buoy, and an ultrasonic array. Comparison between radar cross section (RCS) and Doppler modulations shows peak values occurring nearly in-phase, in contrast with tilt modulation theory. Spectral comparisons between Doppler-based and RCS-based spectra show that Doppler-based spectra demonstrate greater sensitivity to swell-induced modulations, whereas RCS-based spectra showgreater sensitivity to small-scale modulations (or generally have more noise at high frequency), and they equally capture energy at the wind wave peak. Doppler estimates of peak period were consistent with the conventional sensors, whereas the RCS differed in assignment of peak period to wind seas rather than swell in a couple of cases. Higher order period statistics of both RCS and Doppler were consistent with the conventional sensors. Radar-based significant wave heights are lower than buoy-based values and contain nontrivial variability of ∼33%. Comparisons between HH and VV polarization data show that VV data more accurately represent the wave field, particularly as the wind speeds decrease.

show abstract

“…Such a configuration mitigates the problem of the buoy submersion while preventing the buoy from getting adrift (de Vries, 2007). Other potential disadvantages of this innovative system are the possible errors and biases of the GPS measurements, classified as satellite-dependent errors, signal propagation-dependent errors and receiver-dependent errors (Joodaki et al, 2013). In this work, a GPS-based DWSD, recently developed by the Lagrangian Drifter Laboratory (LDL) at Scripps Institution of Oceanography (SIO), is evaluated.…”

Section: Introductionmentioning

confidence: 99%

A New Strategic Wave Measurement Station Off Naples Port Main Breakwater

Centurioni

Braasch

Lauro

et al. 2017

Int. Conf. Coastal. Eng.

View full text Add to dashboard Cite

The accuracy of directional wave spectra sensors is crucial for obtaining accurate forecasts of ocean and coastal wave conditions for scientific and engineering applications. In this paper, a newly designed, low-cost GPS-based wave buoy, called the Directional Wave Spectra Drifter (DWSD), is presented. A field test campaign was conducted at the Gulf of Naples, Italy with the goal of comparing the directional wave properties obtained with the DWSD and with a nearly co-located bottom-mounted Acoustic Doppler Current Profiler (ADCP) from Teledyne RD-Instruments. The comparison shows a very good agreement between the two methodologies. The reliability of this innovative instrument and its low costs allow a large variety of applications, including the implementation of a global, satellitelinked, real-time open-ocean network of drifting directional wave spectra sensors and monitoring the sea-state in harbors to aid ship transit and for planning coastal and offshore constructions. The DWSD is currently in use to better constrain the wave energy climatology with the goal of optimizing the design of a full-scale prototype Wave Energy Converter (WEC) in the port of Naples, Italy.

show abstract

Ocean Wave Measurement Using GPS Buoys

Cited by 20 publications

References 12 publications

Removing low-frequency artefacts from Datawell DWR-G4 wave buoy measurements

Removing low-frequency artefacts from Datawell DWR-G4 wave buoy measurements

Comparison of Incoherent and Coherent Wave Field Measurements Using Dual-Polarized Pulse-Doppler X-Band Radar

A New Strategic Wave Measurement Station Off Naples Port Main Breakwater

Contact Info

Product

Resources

About